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Noncommutative Maslov Index and Eta Forms

Charlotte Wahl
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Abstract

We define and prove a noncommutative generalization of a formula relating the Maslov index of a triple of Lagrangian subspaces of a symplectic vector space to eta-invariants associated to a pair of Lagrangian subspaces generalizing a result of Bunke and Koch in the family case. The noncommutative Maslov index, defined for modules over a $C^*$-algebra $\A$, is an element in $K_0(\A)$. The generalized formula calculates its Chern character in the de Rham homology of certain dense subalgebras of $\A$. The proof, modelled on the proof by Bunke and Koch, is a noncommutative Atiyah-Patodi-Singer index theorem for a particular Dirac operator twisted by an $\A$-vector bundle. We develop an analytic framework for this type of index problem.

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Charlotte Wahl. 2006-05-06. Noncommutative Maslov Index and Eta Forms. https://arxiv.org/abs/math/0309323

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